Brain lesions in the mouse fetus caused by maternal administration of monosodium glutamate (Preliminary report)

Abstract

One mg/g monosodium glutamate (MSG) was given subcutaneouasly to neonate CF#1 mice on day 2 or 4 after birth according to Olney's procedure. They were examined in sections under a light microscope 3 or 6 hours after the treatment, and results similar to those shown by him were confirmed. Then, the same strain of the mouse was treated with 5 mg/g MSG on day 17 or 18 of pregnancy subcutaneously. Fetal brains were similarly examined 3, 6 and 24 hours after the treatment. Similar necrosis of the neural element was detected in groups administered. Frequency of the involvement seemed to be higher in group treated on day 18. Cellular necrosis was seen both in the ventromedial and arcuate nuclei. In those examined on day 17, lesions were more predominant in the ventromedial nucleus than in the arcuate nucleus. These lesions in the ependyma fronting the 3rd ventricle especially in the ventral part of it. In those observed 24 hours after the Injection, no cases showed the lesion in the medial ventromedial nucleus in those treatedon day 17 or 18. Whether the recovery process had taken place or no lesions had originally arisen was difficult to venture. Further, relationship between susceptibility of the brain tissue involved and the maturity of the cell also required further studies. Monosodium L-aspartate (MLA) caused similar lesions in the fetal brain. Generally, lesions caused by MSG or MLA present findings similar to those shown in adult mice by goldthioglucose (GTG).